class_docstr: A representation of a node in the Tree
  Contains two main types of information:
      - Data relevant for the node
      - Links to children nodes
code: def split(self):
      return self._split
  
imports: from typing import Union, Tuple
  from .data import Data
  from .split import Split, SplitCondition
label_desc: Use image node_id 5 for calling the TreeNode obj's underlying member method code with example usage: obj.split() and returns: self